<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>

<body>
    <script>
        // 创建对象
        var obj = new Object();
        obj.name = "海尔";
        // 增
        obj.age = 18;
        // 删
        delete obj.age;
        // 改
        obj.name = "兄弟";
        console.log("name" in obj);
    </script>
</body>

</html>